I was pleased to see some sense finally reported on the comparison between harm caused by alcohol versus that by cannabis.
A Professor of Psychiatric Epidemiology and Youth Mental Health, from the Royal College of Surgeons in Ireland, Dr Mary Cannon pointed out the argument - that alcohol is legal and more harmful to people than cannabis, therefore cannabis should be legal too - is redundant.
Or as the professor describes it, "a spurious argument along the lines of 'would you rather be run over by a truck or a bus'."
It's a cop-out for pro-cannabis legalisation lobbyists to argue along these lines, because the one big elephant in the room is psychotic disorder.
Cannabis use is now the most powerful single environmental risk factor for psychotic disorder, according to studies both recent and ongoing.
According to a Herald report, one study the professor was involved in found that "10 per cent of the young people who'd been using cannabis by age 15 developed a psychotic disorder in young adulthood".
She argues that the association between cannabis and psychosis appears to be getting even stronger in line with the increase in strength of cannabis. That's the THC content – which is now regularly over 20 per cent, and much higher than what it used to be.
Cannon says that in her clinical experience, she's seen an "increase in presentations of young men with psychosis related to cannabis over the past few years".
This includes high levels of agitation, aggression and paranoia.
She also cites "several large international studies ... which have shown that cannabis use in youth has a more detrimental effect on cognition and later functioning in adulthood ... than alcohol use does".
And if that wasn't enough, we have local examples too. A "study from Christchurch showed that young cannabis users had greater rates of school dropout, unemployment and dependence on social welfare payments ..."
And, a "Dunedin study showed that young cannabis users had lower incomes later in adulthood than their alcohol-using peers. Heavy, early onset cannabis use has been associated with up to 8-point drop in IQ that appears to be irreversible."
So why are we playing with fire here? Why would we want to normalise this and pretend the harms aren't real?
Often the people arguing for cannabis legalisation are adult casual users, not young adolescents who'll be most impacted by it. The casual pot-smoking luvvie may well buy or grow the legalised amounts and varieties, but the kids won't.
They'll still seek out black market cannabis with dangerously high levels of THC, still propping up gang manufacture.
So, what changes? The message. The message from the adults around them - and the government - that cannabis is OK.
You legalise something, you normalise it. If you want to stack up an argument around cannabis and alcohol – that's surely it.
Look at all the harm alcohol has created. And you want to add cannabis to the mix? Why would we be so dumb?